Process for cooling internalcombustion engines



Feb. 17, 1948. E. P BARTLETT ET AL 2,436,281

PROCESS FOR COOLING INTERNAL-OOMBUSTION ENGINES Filed March l, 1944 E we W n MM IN VEN TORS TTORNEY Ians C. Duus vent corrosion in the oil valve 2 is open, and means for Patented Feb. 17, 1948 maar 'r ori-fics Paocass Fon cooLING rNrnnNsL- coMnUsnoN nNoxNns asma r. ns1-tlm and nous, Wuming#l tom Del.. ossimoro to l. I. du Pont ilmington.

Company, W Delaware This linvention relates to improvements in processes for` cooling internal combustion engines, and particularly to improvements in proc esses employing antifree ing systems of internal combustion engines.

Hitherto it has been customary to employ as internal combustion engine coolants aqueous solutions of'monohydric or polyhydricalcohols together with various corrosion inhibitors,4 antioxidants and the like. In certain instances, nonalcoholic freezing-point depressants, such as calcium chloride, magnesium chloride, or sodium lactate have been used, but these materials generally have been somewhat corrosive.

An object of-the present invention is to provide an improved method for cooling internal combustion engines. Another object is tovprecooling systems of internal combustion engines by the use oi' a non-alcoholic, yet non-corrosive, freezing-point depressant.

With the foregoing. objects in view, this invention comprises the method o! cooling internal combustion engines by means of a sealed cooling system containing aqueous ammonia, preferable in the absence of air or oxygen. Thus, the present invention contemplates a cooling systeml containing a hermetically sealed-in cooling liquid comprising aqueous ammonia. This is illustrated compositions in the coolde Nemours Delsa corporation of x Anuman Mms i. im, sensi N. sans.

` s cnam.,v icl. iss-1w 'I'hesystem lis then sealed, and operation of the engine is started. When the temperature o i' the coolant reaches 180 1i'.v the gauge pressure on Q the system is 29 pounds vper square inch. At a temperature of 230 F., the gauge pressure is 'I9 pounds per square inch. The mixture in the system, in this illustration, has a freezing point of 440 F.

Figure 1 illustrates an engine cooling system containing aqueous ammonia, and provides a cross-sectional-view of a-means I for withdrawingv air from the system. In normal operation oi' the engine the valve 2 and the sealing device lremains closed, i. e. the system is completely fsealed. Figure 2 also illustrates an engine cooling system 'containing aqueous ammonia, with the air withdrawing'means I and the valve 2 suitably positioned. After the suction has been in the accompanying diagrammatic drawing which shows an engine cooling system containing ammonia. means for expelling air by applying suction to the outlet tubey i while the shuthermetically sealing the system, viz. the shut-oi! valve 2, and the sealing device l.

. In the practice ot this invention it is preferable that the cooling system, bei'ore sealing. be de-aerated so that the vapor above the antifreeze liquid consists largely or almost exclusively oi' water and ammonia. By keeping the system free of air, corrosion of copper and other oxidiza able metals is prevented or greatly diminished. The preferred concentration of ammonia in the applied.v as illustrated in Figures 1 and 2,' the valve 2 is closed, and the aqueous ammonia circulates through the engine in the de-aerated sealed cooling system.

'I'he advantages of the present invention reside not only in th'e excellent physical properties of the antiireeze composition, but also in its chemical inertness towards most metals, andl inI its low cost. The sealing of the cooling system not only prevents excessive loss of the constituents ot the antifreeze composition. but also eliminates the iniiux of air into the system. thus protecting a the metals against corrosion.

antifreeze liquid is about 5% to 30% by weight.

although adequate protection against freezing is obtained at 10% to 20% concentration.

In a speciic illustration. an automobile eny gine water jacket is charged with a 20% solution of ammonia inwater, and a suction is applied. thus'expelling the air from the'free space.

Whileit is desirable, for best results, that air be excluded from the sealed cooling system, this is not always necessary. Thus, the exclusion of air is less important when the metals-with which the antii'reeze mixture comes incontact are noncupreous, such as steel or aluminum.

We claim:

1. A method for preventing corrosion the cooling systems oi' internal combustion engines which comprises cooling the said engines by means of a medium consisting of an aqueous medium containing from 10% to 20% -by weight of ammonia as a freezing point depressant in a cle-aerated, henneticallyssealed cooling system.

2. A method for preventing corrosion in the cooling systems of internal combustion engines which comprises cooling the said engines by means of an aqueous solution containing about 3 4 Y 5% to 30% by weight o! ammonio, in n de- UNITED STATES PATENTS unrated, numerically aetlod miem. Numb Nm D,

a. In n proces for preventinz corrim in th '114,152 am Nov. 16. 1904 cooling Item 01 In 111211151 Nimmo!! 91181115, 1 643,337 my Nav, a, 1937 the mpc which comprise mtrodudns into the l 1:45am; um, mmm, ma nld cooling system ln aqueous solution oontsin- 1,790,573 mt, gm 37. 1931 inl 10% *0 3* b1 "18m 0f mmm Dem 2,114,238 mmm Apr. 12, ma thenlrfromthelaldcoolingsmnndaeaunz the miem so .vom aman lou of the comm- FOREIGN PATENTS uentl ot the ldd solution. l. Number Colmtry Date EDWARD P. BARTIETI. 339,194 England Dec. 4, 1930 m c' Dm' 01m ons. 3mm mm- Uses and Applltions o! Chemicals md Re- Tho following :um m o! record 1n the ll ted will, GMO". Reinhold Pub. Com

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Bcientm Librll'y.)

Certificate of Co1rtffe .t.en Patent No. 2,436,281. February 17, 191:3.v EDWARD P. BARTLETT ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Column 1 line 4, for antifree read antolfreeze; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 27th day of April, A. D. 1948.

[BML] THOMAS F.- MURPHY,

Assz'sta/nt Uommz'ssoner of Patents. 

